Richard P. Grant
rgrant at netscape.net
Tue Sep 12 02:44:10 EST 2000
In article <8pifho$qdb$1 at news.ox.ac.uk>, "James Sandy"
<james.sandy at pharm.ox.ac.uk> wrote:
> Hi there, I have a problem. I am purifying arylamine n-acetyltransferase
> the prep is fine until the protein is being concentrated. Around 5 mg/ml
> protein seems to aggregate and fall out of solution. Does anybody know
> cunning methods to stop proteins falling out of solution when being
Hi. There are, IME, two buggers that cause 'difficult' aggregation (i.e
changing away from the pI does not help - which of course you should
try). The first is proteolytic degradation. The second is the presence
of hydrophobic patches on the protein (this how degradation effects
aggregation). You can test for the second possibility by keeping the
prep at 4C, or adding up to about 33% glycerol or ethylene glycol.
Both approaches should inhibit hydrophobic interactions.
Richard P. Grant MAD Phil http://www.gerbil.org.uk/
Please reply to rpg 'at' mrc-lmb.cam.ac.uk'
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